Re: [PATCH] mmc: dw_mmc: use the use_hold_reg bit in CMD register

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On 30 September 2011 16:16, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
> This patch is added the use_hold_reg bit in CMD register.
>
> In 2.40a, bit[29] of CMD register is used the use_hold_reg.
> Some SoC is affected by this bit.
> (This bit means whether use hold register when send data and cmd.
>  And related with cclk_in_drv phase)
> if set IMPLEMENT_HOLD_REG in HCON register, i think fine that set this
> bit by default.
>
> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
>  drivers/mmc/host/dw_mmc.c  |    9 +++++++++
>  drivers/mmc/host/dw_mmc.h  |    1 +
>  include/linux/mmc/dw_mmc.h |    1 +
>  3 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 0ed1d28..544a616 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -276,6 +276,13 @@ static void dw_mci_start_command(struct dw_mci *host,
>        mci_writel(host, CMDARG, cmd->arg);
>        wmb();
>
> +       /*
> +        * If use HOLD register,
> +        * CMD and DATA sent to card through HOLD register.
> +        */
> +       if (host->use_hold_reg)
> +               cmd_flags |= SDMMC_CMD_USE_HOLD_REG;
> +
sorry for seeing the patch very late.
I think its not just enough to check the HCON register. it is also
necessary to check whether CLKSEL[18:16] field is not 0 in combination
with HCON

>        mci_writel(host, CMD, cmd_flags | SDMMC_CMD_START);
>  }
>
> @@ -1886,6 +1893,8 @@ static int dw_mci_probe(struct platform_device *pdev)
>                host->data_shift = 2;
>        }
>
> +       host->use_hold_reg = (mci_readl(host, HCON) >> 22) & 0x1;
> +
>        /* Reset all blocks */
>        if (!mci_wait_reset(&pdev->dev, host)) {
>                ret = -ENODEV;
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index bfa3c1c..8c4edca 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -102,6 +102,7 @@
>  #define SDMMC_INT_ERROR                        0xbfc2
>  /* Command register defines */
>  #define SDMMC_CMD_START                        BIT(31)
> +#define SDMMC_CMD_USE_HOLD_REG         BIT(29)
>  #define SDMMC_CMD_CCS_EXP              BIT(23)
>  #define SDMMC_CMD_CEATA_RD             BIT(22)
>  #define SDMMC_CMD_UPD_CLK              BIT(21)
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index 6b46819..d6d1515 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -147,6 +147,7 @@ struct dw_mci {
>        u32                     current_speed;
>        u32                     num_slots;
>        u32                     fifoth_val;
> +       bool                    use_hold_reg;
>        struct platform_device  *pdev;
>        struct dw_mci_board     *pdata;
>        struct dw_mci_slot      *slot[MAX_MCI_SLOTS];
> --
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